linux-kernel - [PATCH] media: dvb-usb: m920x: Fix a potential memory leak in m920x_i2c

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Message-Id: <1881e72f963ec25e35b34f3a0b4f3962681eb7ca.1685339897.git.christophe.jaillet@wanadoo.fr>
Date:   Mon, 29 May 2023 07:58:36 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        linux-media@...r.kernel.org
Subject: [PATCH] media: dvb-usb: m920x: Fix a potential memory leak in m920x_i2c_xfer()

'read' is freed when it is known to be NULL, but not when a read error
occurs.

Revert the logic to avoid a small leak, should a m920x_read() call fail.

Fixes: a2ab06d7c4d6 ("media: m920x: don't use stack on USB reads")
Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/media/usb/dvb-usb/m920x.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/dvb-usb/m920x.c b/drivers/media/usb/dvb-usb/m920x.c
index fea5bcf72a31..c88a202daf5f 100644
--- a/drivers/media/usb/dvb-usb/m920x.c
+++ b/drivers/media/usb/dvb-usb/m920x.c
@@ -277,7 +277,6 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu
 			char *read = kmalloc(1, GFP_KERNEL);
 			if (!read) {
 				ret = -ENOMEM;
-				kfree(read);
 				goto unlock;
 			}
 
@@ -288,8 +287,10 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu
 
 				if ((ret = m920x_read(d->udev, M9206_I2C, 0x0,
 						      0x20 | stop,
-						      read, 1)) != 0)
+						      read, 1)) != 0) {
+					kfree(read);
 					goto unlock;
+				}
 				msg[i].buf[j] = read[0];
 			}
 
-- 
2.34.1